Peak voltage indicating and measuring system



Oct. 5, 1954 H. H. WITTENBERG PEAK VOLTAGE INDICATING AND MEASURING SYSTEM Filed Nov. 29, 1949 3nnentor Hu BERT H. WITTENBERE Ctttomeg Patented Oct. 5, 1954 PEAK VOLTAGE INDICATING AND MEASURING SYSTEM Hubert H. Wittenberg, Lancaster, Pa., assignor to Radio Corporation of America, a corporation of Delaware Application November 29, 1949, Serial N 0. 130,051 6 Claims. (01. 340253) This invention relates to improvements in voltage measuring apparatus, and particularly to apparatus for determining maximum and minimum peak values of electrical pulses.

In making electrical measurements, it often is necessary to determine the maximum and minimum peak values of pulsating voltages of varying amplitude. For example, in determining the control characteristics of a gas tube, such as an terminals [9. Consequently, the two gas tubes I0, l2 will receive positive half-cycles of anode voltage alternately, so that only one of the gas tubes can be conductive at any given time.

The gas tubes l0, l2 each have an on-off indicator connected in circuit therewith to respond to current conduction in the tubes. For example, resistors 2|], 22 are shown connected in series with the tubes [0, I2, respectively, and so-called excitron or the like, in measuring vacuum tube neon glow tubes 24, 26 are connected in parallel noise characteristics, resistor and atmospheric with the anode load resistors 20, 22, respectively. noise characteristics, and nucleonic radiation, it When either gas tube is conducting, the indicator is often essential to determine the maximum and associated therewith Will be energized by the i i m peak val of voltage pulses of ranvoltage developed across the load resistor of the domly varying magnitude. l5 conducting tube.

It is, accordingly, a general object of the pres- One Of e gas tu has its Cathode conent invention to provide an apparatus for measnected through a resistor 28 to a source of variuring electrical phenomena of the foregoing type. able s V e 30, Shown as a battery 32 having A more specific object of the invention is to a potentiometer 34 connected in shunt therewith. prgvide an t i l measuring apparatus The control grid of the gas tube It] is connected wherein on-off indicators are utilized to facilitate t0 the potentiometer arm a gh a d curmeasuremem of maximum and minimum i rent limiting resistor 36 and a grid return resistor tri i pulse v l 38, and a voltmeter 40 is connected across the In accordance it th i ti th foreoutput side of the bias voltage source 30 to measgoing and other related objects and advantages lire the e e tive bias applied to the tube 10. are attained by providing a circuit containing two The Voltage pulses P o b measured are pelectron tubes energized with alternating voltages plied to the apparatus u h a p of put and so interrelated that only one of the two tubes terminals 42 connected to ppo e ends of the is conducting at any given time. Th two tubes grid return resistor 38, so that the tube ID will are so arranged that one of the tubes conducts 9011611191? current y When o Or more of the substantially continuously when the pulses being lhcomlng pulses has e er peak Voltage value measured are almost all larger than a predeterthan the Selected Value Of bias Voltage pp e mined minimum value, while the other tube conto the tube ducts substantially continuously when the pulses The Second gas tube l2 as its cathode conbeing measured are almost all maller than a nected to one end of 13116 cathode load resistor 28 predetermined maximum value. O-n-off indi- 0f the first gas tube and the Control g d of Gators connected t each of the tubes provide the tube 12 is connected to the cathode end of readily perceptible indications when the circuit the cathode load resistor 23 u h a Self-bias is in either of the two stated conditions network 44 comprising the parallel combination A more complete understanding of the haven- Of a resistor and a capacitor 48. The time tion can be had by reference to the following deconstant of the network 44 s ould be Slightly scription of an illustrative embodiment thereof greater than one half e iod of the alternatwhen considered in connection with the accommg anode Voltage, for a purpose to be described panying drawing, the single figure of which is a hereinafterschematic diagram of apparatus arranged in ao- 45 In cohsldeling the Opera-$1011 0f the apparatu cordance with the invention. it can be seen that when a high value of bias volt- Referring particularly to the drawing, the apage is Selected for the first gas tube y e paratus. shown comprises two tetrode-type gas setting of the potentiometer arm 34a, the tube filled electron tubes [0, l2, each furnished with [0 will not conduct any current, and its indicator alternating anode voltage through a pair of 24 will be extinguished. At the same time, the transformers l4, I6. The primary windings of grid and cathode of the second gas tube I2 will the transformers are connected to a transformer be substantially at the same potential, so that the 18 in opposite phase relation and the transformer tube 12 will ignite on each positive half-cycle of i8 is connected to any suitable source of altervoltage applied to the anode thereof thru the nating voltage (not shown) through a pair of transformer l6, thereby energizing the indicator 26. Due to persistence of vision, the indicator 26 will appear to be energized continuously under the circumstances just described.

By gradually reducing the bias on the first gas tube in, a bias value eventually will be reached at which the largest incoming pulses will overcome the bias voltage and cause the tube It to fire occasionally, thereby causing the indicator 24 to flash, indicating that the largest incoming pulses are just large enough to overcome the bias voltage from the source 30. Each time that the tube I fires, the resulting voltage pulse developed across its cathode resistor 28 will be applied to the grid of the second gas tube 12 through the bias network 44. These positive pulses will cause the tube l2 to draw grid current, thereby charging the capacitor 48 with a negativev charge on the grid side of the capacitor.

As was stated, the time constant of the resistorcapacitor combination in. the bias circuit 44 is made l s v' a r' han one half the period of the alternating anode voltage. Hence, the capacitor 48.. will hold a charge developed therein during the next succeeding positive half-cycle of voltage on the-anode of the tube l2, and the tube [2 will be held cutoff for one-half cycle, so that the indicator 26 associated therewith will be deenergized momentarily. However, the occasional on condition of the first indicator 2:4 is much easier to. detect. than the occasional off condition of the second indicator 26. Hence, the first indicator 24 will be relied on to provide an indication of circuit conditions corresponding to maximum pulse input voltage, and the reading of the voltmeter then will be substantially equal to the. maximum peak value of the applied voltage pulses.

Havin established the maximum peak value of the incoming pulses in the foregoin manner, the biason the first gas tube now is decreased by further adjustment of the potentiometer arm 34a, causing t e first gas tube Ill to ignite more frequently, and causing the second tube l2. to be cut off for a greater proportion of the time, than was previously the case. Eventually, a bias value will be reached at which the first indicator 24 will appear to bev energized continuously, while the second. indicator 26 will appear to be ofi substantially all of the time but will resond occasionally. This condition will indicate that almost all of the incoming pulses are firing the first tube In, which means that the bias voltage on the tube 10 is only slightly more negative than the minimum peak value of the incoming voltage pulses; That is, if the bias voltage on the tube ill were to be decreased only a slight amount more, all of the incoming pulses would be effective to fire the tube l0, the first indicator 24. would respond continuously,- and the second indicator 26 would remain deenergized all the time. Consequently, the reading of the voltmeter All now will be proportional to the minimum peak value of the incoming pulses.

Accordingly, it can be seen that an occasional ofi cycle of either tube, Illw or 12, which would be relatively difiicultto detect, will appear as an occasional on cycle of the other tube, and can be detected readily by resonse of the indicator associated with that tube to indicate the condition of the circuit.

What is claimed is;

1. In an apparatus for determining the max imum and min m m pea v lu s f l a p lse in combination, a first circuit, a source of alternating current potential, means including an impedance for connecting said source to said apparatus, a source of voltage pulses to be measured, means whereby said first circuit is conductively responsive only to pulses of peak value greater than a selectable predetermined magnitude from said voltage pulse source, a second circuit,,means including: an impedance for connecting said second circuit in reversed. phase to said alternating voltage source, means connecting said circuits to cut oil current flow in said secondcircuit inresponse to current fiow through said first circuit, said means including an impedance element in said first circuit across which todevelop a voltageby current fiow through said first circuit, and means to indicate current flow in each of said circuits.

2. In an apparatus for measuring maximum and minimum values of voltage pulses, in combination, a pair of input terminals adapted to be connected to a source of voltage pulses to be measured, a source of alternatin Vol age f f quency less than. the recurrence rate of said pulses, a first gas filled tube connected to. rec ive a first alternating operating voltage from said source, a second gas filed tube connected to receive a second alternatin voltage from said source and normally conductive during each positive half cycle of said second alternating voltage, said first and secondvolta es being of pposite phase, means to indicate current flow in each of said tubes, means to, initiate current flow in said first tube in response to the rec pt of volt age pulses of greater than predetermined magnitude, and means connecting said tubes to out off current flow in said, second tube in response to current flow in said first. tube.

3. In. an apparatus for determining the maximum and minimum peak values of pulsating voltages of differing peak magnitude, in combination, a. source of alternating voltage, a first gas filled tube having anode and cathode electrodes. a circuit connecting said first tube to Said source to apply a first alternating voltage between said electrodes, a second a fi led. ube h ving, no and cathode electrodes. a ircui onn cting said second tube to said. source to apply between said second tube electrodes a sec nd alternating v lt a e. opposite in phase to said first. alternating volta e, mean to indica e curren flow in each of. said tubes, means. to. establish current flow in said first tube only response. to. a voltage pulse of greater than predet rmined magn ude, and means connectingsaid tubes. to interrupt. current flow in. said sec nd tube in esponse to current flow'in. said firsttube e. n a apparatus for. determining he maximum. and minimum p els; v ue of voltage pulses. in. combination, a sou ce of; alternating current potential, a first pair of terminals including a first. impedance adapted to e conn c ed to ai source. a s c nd pair of. erminals including a second impedance a apted o b co n cted t a source 025 voltag pulses to be measured. a first circuit connected to said. terminals and means whereby said first circuit isconductively respon sive only to pulses of peak valuegreater than a selectable predetermined magnitude from said voltage pulse source, a second circuit connected in reverse phase to said first pair of terminals, means connecting said circuits to cut off current flow in said second circuit in response to current fiow through said first circuit, said means including an impedance element in said first circuit across which to develop a voltage by current flow through said first circuit, and means to indicate current fiow in each of said circuits.

5. In an apparatus for determining the maximum and minimum peak values of voltage pulses, in combination, a pair of gas filled tubes each having at least an anode, a grid, and a cathode, a first and a second circuit each including one of said tubes, means in said circuits connecting the anodes and the cathodes of said tubes across a source of alternating operating voltage, means connecting said first circuit to said second circuit tube to prevent current flow through said second circuit tube in response to current fiow through said first circuit tube, means in said first circuit to indicate current flow through said first circuit tube, means in said second circuit to indicate current flow through said second circuit tube, means in said first circuit to connect said first circuit to a source of said voltage pulses to be measured, and means in said first circuit to initiate current flow in said first tube only when the voltage pulses applied to the grid thereof are of a greater than predetermined magnitude.

6. In an apparatus for determining the maximum and minimum peak values of voltage pulses of similar polarity, in combination, a first and a second gas filled tube each having an anode,

, trol grid and cathode to said first tube to cut off current flow through said second tube when current flows through said first tube, and means coupled to each said tube to indicate current fiow through said tubes.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,050,250 Aggers Aug. 11, 1936 2,125,992 Collings Aug. 9, 1938 2,139,474 Shepard Dec. 6, 1938 2,185,192 Hansell Jan. 2, 1940 2,249,323 Mitchell July 15, 1941 2,299,272 Hallden Oct. 20, 1942 2,403,988 Likel July 16, 1946 2,422,766 Alexander June 24, 1947 2,547,511 Weissman Apr. 3, 1951 

